Heat-treating furnace



Dec. 11, 1928. 1,695,224

A. BESTA HEAT TREATING FURNACE Filed March 26, 1926 3 Sheets-Sheet 2Dec. 11,1928.

A. BESTA HEAT TREATING FURNACE Filed March 26, 1926 3 Shets-Sheet 5Patented Dec. 11, 1928.

UNITED STATES 1,695,224 PATENT oFFicE.

AD-ALBERT BEST A, or DUISIBURG, GERMANY.

HEAT-TREATING FURNACE.

Application filed March 26, 1926, Serial No.'97,715, and in GermanyFebruary 28, 1925.

The method used hitherto for annealing ing plants, if the material ormetal is tobe annealed in a neutral gas. The present 1nvention relatesto a method which has very considerable advantages over the annealing,

in methods used hitherto, as regards output, space required andefficiency. In the new method the materials or metals to be treated aresuperposed on one another in layers in a suitable ap aratus, are forcedupward 5 either verticall y or at an angle, are heated whilebeing soforced upward, are moved aside when.they=have reached the top and arethereupon conveyed downwards either vertically or at an angle and arecooled while being so conveyed. Preferably the pieces of material ormetal are put into containers which travel through the annealingapparatus in the manner described. The material to be passed through theapparatus is forced upwards by means of a charging device and isconveyed downwards by a delivery device. If the annealing is to becarried out in the inert gases, a closing member is provided above'thecharging device and another above the delivery device, so that the otherpart of the annealing apparatus can be shut off when the material isbeing introduced and delivered to the charging device or deliveringdevice. The spaces in which thecharging and delivery devices are housedarecapa ble of being-shut off to the outside, so that after the closingmembers have been opened, the material to be annealed is conveyedupwards or downwards without any danger of the outer air mixing with theinert gas. After the material to be annealed has been placed on thecharging device, the space is closed to the outside and is placed undervacuum, so that the air in the said space is removed. The spacesthereupon filled with inert gas, the upper closing member is opened andthe material to be annealed is forced upwards, after the material beingannealed, which lies at the top, has been displaced to the side. Bymeans of the delivery device the material is thereupon conveyeddownwards and the closing member on this side is closed so that thematerial can be led away to the side after the lower space has been 5opened. The space containing the delivery device is then closedagain, isevacuated and is filled with inert gas. When the charging v and deliveryspaces are being evacuated the pressure must be observed at the closingably caused to flow downward in such a. manner that the downwardlyconveyed flow of gas is so divided that a portion of the said gas ispassed by the action of a blast through '75 heaters and returned to theapparatus at the top-,while the other portion is conveyed downwardsgiving ofi' heat to the material or metal, as it is conveyed upwards ordownwards, whence, cooled down to 'a certain temperature it is conveyedby mechanical means to the blast arrangement located in? front of theheater. Should the stream of gas emerging at the bot-tom still have toohigh a temperature for the purposes of mechanical conveyance, it may becooled down by suitable cooling devices before entering the mechanicalconveying device. Between the mechanical conveying device and the blastproducing device the conveyed gas may be heated in heaters to such anextent that behind the blast producing device it will be only necessaryto heat the gas for accurate temperature regulation. The amounts of heatrequired for heating up the inert gas are supplied to the heaters by thegiving ofl" of combustion heat or by the production of electricalresistance heat or by these two methods of supplying heat. As the purelyelectrical method of heating is uneconomical m0 owing to the high costsinvolved, the greater part of the heat required may be produced bycombustion heat and the electric heating be used only for accuratelyregulating the annealing temperatures. In order that the 1 5 material tobe annealed by he passed through rapidly, the inert gases are preferablycirculated in the lower part of the annealing furnace independently ofthe upper part by mechanical means with or without cooling no 70 Itemperature everywhere. The gas is prefermeans, in order that thematerial or metal parts to be removed from the furnace are cooled andcan be moved as quickly as possiveyance of the material or metal partsare preferably so constructed that the gases can be freely circulated inthe annealing furnace. Thus for instance two opposite sides may beprovided with apertures and the material to be annealed be laid inlayers in the containers in such a manner that the inert gases sweethrough the containers either'heating or a sorbing heat or giving offheat. In order that the conveyors for the material to be annealed may beconveniently superposed onone another, they are preferably madebox-shaped and are provided with lateral lugs for preventing them fromsliding down. In the case of the ascending boxes one or more shaftswhich roll on inclined supports are pushed aside by the lateral lugs onthe boxes until, on the boxes being raised still further, the shaftsslip under the lugs, so that the boxes are held up, on the lifting meansmoving back again. For conveying the boxes downwards two, four ormorespring supported means are provided forcing the shafts back, which, whenthe discharging means are performing their upward motion, engage underthe supporting shafts, are stressed until the discharging means raisedthe box, thereupon push the released shafts aside and prevent the shaftfrom engaging under the lugs on the box, so that, on the dischargingmeans being lowered, the shaft-s will only arrest the next box. In orderthat the annealing furnace can be erected in a simple manner, the guidesin which the boxes slide with the gas conveying passages and the heatingdevices are built up of superposed parts having a circular periphery andfastened together. For preventing gas losses a pressure tight metalsheathing is placed around the entire apparatus, which is separated byan insulating layer from the built up sections lying within it, so thatas little heat as possible will be lost by radiation. For savingoperating costs and for shortening the duration of the process thesucces- Sheets I to III, a constructional example of the invention isshown. Fig. 1 on Sheet I shows a sectional elevation of an anneallngfurnace working according to the new ,method, in which there isnoprovision of means for guiding heating gases, and in whlch the upperchamber is electrically heated. Fig. 2, Sheet II, is a sectionalelevation through another constructional form of the furnacerepresenting the arrangement for the deflecting method. This form of thefurnace is provided with inserted guides for heating gases. In the caseof this furnace the heating is effected b circulating hot gases in theupper part of t e furnace, with branch currents of the hot gases towardsthe central part of the furnace, the figure showing the Way the gasesare guided, the heaters, and the mechanical means for conveying thegases and the coolers. Figs. 3 to 5 on Sheet III show the constructionof the annealing boxes, the means for holding the boxes in position andthe charging and delivering means, Fig. 3 being a section on the lineIII-III in Fig. 1, at right angles to the plane of the drawing, Figure 4a section on the lineIV-IV in Fig. 1 in the same plane as thedischarging device, and Fig. 5 a section on the line VV in Fig. 3.

In the annealing furnace shown in Fig. 1 on Sheet I the'annealing boxes2 filled with material or metal parts are conveyed to the furnace ontrolleys 39, provided with antifriction rollers 41 and introducedthrough the closing door 3 into the charging space 4, where it restsupon anti-friction rollers 42 on the top of a charging device 6. Afterthe door 3 has been closed the space 4 is evacuated and thereupon filledwith inert gas. After the closing member 5 has been opened the annealingboxes are raised by the charging device 6 into the position 2. The boxesare automatically arrested in this position, so-

that after the charging device 6 has been lowered the sliding member 5can be closed. The annealing box which is in the position 2" isthereupon pushed by the pressure applying means 7 into the position 2,the sliding member 8 at the bottom opened and the annealing box which isin'the position 2 is received upon rollers 43 on the top of adischarging device 9 and lowered by means of the discharging device 9into the discharging space 10. Means are provided for automaticallyholding the annealing box 2 in the position 2 while the lowest box isbeing lowered. The sliding member 8 is there- I upper part of thefurnace at 15 and are guided downwards by the middle bridge members 16and all thefiues 17, being passed through or around the annealing boxes.In the lateral flue 18 the stream of gas divides, one portion beingguided downwards in the direction ofthe arrow, having a heat equalizingeffect on the ascending and descending annealing boxes and becomingcooled at the sametime, after which it is conveyed to a blower 20 whichforces it to the blast producing arrangement 21. The second part of thestream of gas is drawn by suction from the lateral flue 18 to the blastproducing device 21cand is passed to the heaters 22 and 23, where it isheated and passed into the furnace again at 15. The heater 22 is heatedby the gas burner 24. The heater 23 is heated electrically and is usedfor accurately regulating the temperature of the gases entering theannealing furnace at 15. In the lowest part ofthe furnace gases arecontinuously deflected in one direction by the blower 25 through thelateral flues 26 and 27 and through the annealing boxes located in frontof the said flues, the said gases being cooled in the cooler 28, afterwhich they pass into the annealing box 2, the material in which is stillin a hot state, thence into the boxes 2 and 2 which are filled withcooled material,

give off heat to the same and are passed through the box 2 which isfilled with hot material to the blower 25. By this way of.

deflecting the gas the downwardly conveyed material can be rapidlycooled, if it should still be too hot to be discharged, so that only ashort time need be provided for. passing through the furnace. Throughthe exchange of heat, which takes place in the middle of the furnacebetween the descending and ascending material, by the branched ofl'stream of gas which flows downwards and by the deflection of the hotgases in the upper part of the furnace the time taken for passing thematerial through the furnace is also considerably reduced and thematerial thoroughly annealed. As the apparatus is built up vertically,it does not occupy much floor.

space. Owing to the utilization of the heat of the descending material,the compact vertical construction of the furnace and the possibility ofefliciently insulating the hottest parts of the furnace, the methodbecomes very economical. In Fig. 3 on Sheet III the arrangement 29 forholding the annealing boxes 2 on the chargin sideof the furnace isshown.

The annealing boxes 2 are provided with a plurality of'lugs 31, which,on the boxes the discharging mechanism is shown which discharges theboxes downwardly from the suspending device shown. in Fig. 3. Thedischarging device 9 comprises a plunger 35,

the upper part of which is provided with rollers 43 and with lateralmeans 36 for pressing the rollers back, which means, on the dischargingdevice being raised, bear against the shaft 32, so that'on thedischarging device continuing to rise, the springs 37 become stressed tosuch an extent that the rollers 34 7 lift the boxes 2. The disengagedshafts 32 are forced aside and the'members 36 slide into the recesses 38(Fig. 5) and lock the shafts 32 in position, so that, on the dischargingdevice returning, the lowest box can be moved downwards withoutobstruction. On the boxes being lowered, the shafts 32 run inwardly overthe lugs 31 and engage under the lugs of the next higher box, which isto be held in position.

Each of the annealing boxes 2 is preferably provided-with a projection45 at the top and a recess 46 at the bottom, adapted to fit over theprojection at the top of the box below it. The rollers 41, 42, 43 and 44are provided with parts 34 of larger diameter, capable of engaging inthe said recesses.

What I claim is 1'. Apparatus for the heatingand subsequent cooling ofmaterials, and more para loosely superposed condition without employinga chain conveyor, means for guiding the materials upwards in theapparatus, means for heating the materials on their upward path throughthe apparatus, a pushing device fitted into the wall of the apparatusfor moving the materials sideways at the highest part of the apparatusand then downwards, means for guiding the materials downwards throughthe apparatus from the :highest point, means for cooling the materialsduring their downward travel, and a discharging device located only inthe lower.

part of the apparatus.

2. Apparatus for the heating and subseprising. means in the upper partof the apparatus for heating the materials to the desired temperature bycirculating heating gases, meansin the central part of the apparatus forexchanging heat between the materials that are being carried upwards andthe materials that are being carried downwards,-and means in the lowerpart of the .quent cooling of materials, and more particularly for theannealing of metals, comdischarging side, lateral lugs on thecontainers, inclined members on the walls of the furnace, shafts capableof resting on the said inclined members and of being forced upwards andoutwards by the lugs of the ascending containers and of thereuponengaging under the said lugs on the upward movementof the containercontinuing and of holding the containers suspended, on the means forraising the containers moving downward again, as set forth.

4:. A furnace as claimed in claim 3, and

comprising on the discharging side a plurality of resilient memberscapable ofpushing the said shafts back and .of engaging under the saidshafts on the lowering means being raised and locking the shafts in thepushed back position and, on the lowering means being lowered, ofarresting the next container as it descends, as set forth,

5. A furnace as claimed in claim 3, and comprising means for introducingthe containers into the furnace, means for raising the introducedcontainers in the furnace, means 6. Apparatus for the heating andsubsequent cooling of materials, and more particularly for the annealingof metals, comprising a heating, heat-exchanging and cooling chamber,means for introducing materials into said chamber at the bottom, meansfor raising said materials to the top of the cha1nber, means forlowering said materials from the top to the bottom of the chamber, meansfor removing said materials from said chamand means in the lower part ofsaid chamber.

for cooling the materials that are to be discharged.

7. Apparatus for the heatingand subsequent cooling of materials, andmore particularly for the annealing of metals, comprising a heating,heat-exchangingand cooling chamber, means for introducing materials'into said chamber at the bottom, means for raising said materials tothe top of the chamber, means for lowering said materials from the topto the bottom of the chamber, means for removing said materials fromsaid chamber at the bottom, means for causing inert gases to travelthrough said chamber, means for deflecting said gases in the upper partof said chamber, means for dividing the downwardly deflected stream ofgas andpassing a-portion v the descending materials, mechanical con-v (Vveying means for passing this second portion of the divided stream ofgas to the blast-producing device, and means in the lower part of thechamber for cooling the materials that are to be discharged.

In testimony whereof I have signed my name to this specification.

i ADALBERT BESTA.

